In an artificial fertilization, sperma of a human or animal donor, which has been collected in a sucking tube made of a plastic material by sucking it thereinto, is discharged out via an open end thereof into the uterus of the female recipient by sliding a plug inserted in the sucking tube towards the open end thereof using a pushing element. In a transplantation of an embryo (fertilized ovum) also, similar procedures as above are pursued, while in this case the sperm is replaced by the embryo stored in a preserving liquor.
In the context of the specification of the present invention, "sperma or the like" is used to refer to sperma or transplantation liquor containing embryo(s), fertilized ovum(s), unfertilized ovum(s) and other cell(s).
In collecting a sperma or the like in a sucking tube, it is sucked into the tube from one end thereof by aspirating the tube internal air from the other end through a gas-permeable stopper made of, for example, sanitary cotton, stuffed in the tube, whereupon the stopper is removed from the sucking tube filled with the sperma or the like, whereupon the tube is sealed again by inserting therein a sterile non-permeable plug, in order to prepare for subsequent artificial fertilization.
For improving the actual procedures of such a laborious practice for collecting sperma or the like in the sucking tube, a technique was proposed meanwhile, in which a stopper composed of a first zone of gas-permeable cotton fibers, a second zone of gas permeable powdery gelatinizing material and a third zone of cotton fibers is stuffed in a sucking tube at one end portion thereof and the sperma or the like temporarily stored in a vessel is sucked up into the sucking tube via the other open end of the tube by aspirating out the internal air in the tube from the stopper-side open end of the tube through the gas-permeable stopper until the sperma or the like reaches the stopper, wherein the sperma or the like reacts with the powdery gelatinizing material to cause it to swell and gel to thereby fill up the tube as an integrated sealing stopper.
In the above technique, the gas-permeable stopper is composed of a powdery gelatinizing material sandwitched between two gas-permeable cotton fiber zones. When a sperma or the like is sucked into the sucking tube having such a stopper inserted therein, a part of the sperma or the like will pass through the inside cotton zone and reach the powdery gelatinizing material. Upon contact of the powdery gelatinizing material with the spema or the like, the gelatinizing material swells by absorbing water from the sperma or the like to fill up the tube and, then, it reaches gellation, while binding with a part of the cotton fibers to build up an integrated sealing stopper. Then, the open end of the sucking tube through which the sperma or the like is sucked thereinto is sealed by welding by an appropriate method, such as an ultrasonic heat treatment, in order to preserve the so-collected sperma or the like therein until it is transferred to the recipient.
However, this technique requires, at least with respect to the preparation of the three-zone stopper in a portion of one end of the sucking tube, three working steps for inserting the first zone of cotton fibers, the second zone of powdery gelatinizing material and the third zone of cotton fiber each in a separate procedure into a thin sucking tube having a inner diameter of, usually, 2.6 mm or 1.55 mm. For such insertion works, a plurality of specifically devised precise instruments are necessary.
This technique is also disadvantageous in that the gelatinizing material is present as a powder and is not only difficult to weigh it minutely but also apt to be scattered around upon its insertion into the tube to thereby pollute the product and assembly and, in some cases, the powder may even be scattered beyond the cotton zone to the collecting space for the sperma or the like and may damage the live activity of the spermatozoon or the embedding rate of fertilized ovum.
In the context of the specification of the present invention, the "gelatinizing material" is used to refer to a material which will swell upon contact with a water-containing liquid, such as sperma or the like, by absorbing water therefrom and reach eventually gellation to build up an integrated sealing stopper together with the supporting fibers. Concrete examples therefor include polyvinyl alcohol, dextrin, casein and the like.